1. Field of the Invention
The present invention relates to an engine-operated generator covered by a soundproof case in its entirety.
2. Discussion of Relevant Art
The engine-operated generator in which an engine and a generator driven by the engine are integrated is used at a construction work site generally. And in consideration of influences to the surroundings when it is operated in a city area especially at night, an engine-operated generator covered by a soundproof case in its entirety has been used widely in order to restrain operation noise to as low a level as possible.
In this kind of engine-operated generator, openings for suctioning or discharging air are made few in number and small in size to achieve necessary low noise level during operation. But on the one hand, it is necessary to devote great care to cooling the interior of the soundproof case because the area of the openings is small.
Japanese Utility Model Publication No. 64-3777 discloses an engine-operated generator in which an engine and a muffler are covered by a duct to be isolated from other instruments and cooling air is forcibly passed through the duct and discharged at the side of the muffler out of the soundproof case so that high temperature cooling air is property discharged and prevented from recirculating into the soundproof case.
However, as for a generator placed outside of the duct in the soundproof case, it is necessary to provide another cooling air passage than the above duct or an exclusive cooling fan for the generator, and therefore the engine-operated generator is caused to be large-sized.
In the engine-operated generator of the Japanese Utility Model Publication No. 64-3777, a fan for cooling the generator is provided separately from a cooling fan for passing air forcibly through the duct covering the engine and the muffler, and air discharged from the fan for cooling the generator is joined in the duct after cooling the generator. Therefore, there is a problem that the air from the generator cooling fan requires a certain high discharge pressure to join in the duct and it is not necessarily an efficient cooling system.